ODBC Scalar Functions (Transact-SQL)

Artikel
05/16/2013

You can use ODBC Scalar Functions in Transact-SQL statements. These statements are interpreted by SQL Server. They can be used in stored procedures and user-defined functions. These include string, numeric, time, date, interval, and system functions.

Usage

SELECT {fn <function_name> [ (<argument>,....n) ] }

Functions

The following tables list ODBC scalar functions that are not duplicated in Transact-SQL.

String Functions

Function	Description
BIT_LENGTH( string_exp ) (ODBC 3.0)	Returns the length in bits of the string expression. Does not work only for string data types. Therefore, will not implicitly convert string_exp to string but instead will return the (internal) size of whatever data type it is given.
CONCAT( string_exp1,string_exp2) (ODBC 1.0)	Returns a character string that is the result of concatenating string_exp2 to string_exp1. The resulting string is DBMS-dependent. For example, if the column represented by string_exp1 contained a NULL value, DB2 would return NULL but SQL Server would return the non-NULL string.
OCTET_LENGTH( string_exp ) (ODBC 3.0)	Returns the length in bytes of the string expression. The result is the smallest integer not less than the number of bits divided by 8. Does not work only for string data types. Therefore, will not implicitly convert string_exp to string but instead will return the (internal) size of whatever data type it is given.

BIT_LENGTH( string_exp ) (ODBC 3.0)

Returns the length in bits of the string expression.

Does not work only for string data types. Therefore, will not implicitly convert string_exp to string but instead will return the (internal) size of whatever data type it is given.

CONCAT( string_exp1,string_exp2) (ODBC 1.0)

Returns a character string that is the result of concatenating string_exp2 to string_exp1. The resulting string is DBMS-dependent. For example, if the column represented by string_exp1 contained a NULL value, DB2 would return NULL but SQL Server would return the non-NULL string.

OCTET_LENGTH( string_exp ) (ODBC 3.0)

Returns the length in bytes of the string expression. The result is the smallest integer not less than the number of bits divided by 8.

Does not work only for string data types. Therefore, will not implicitly convert string_exp to string but instead will return the (internal) size of whatever data type it is given.

Numeric Function

Function	Description
TRUNCATE( numeric_exp, integer_exp) (ODBC 2.0)	Returns numeric_exp truncated to integer_exp positions right of the decimal point. If integer_exp is negative, numeric_exp is truncated to \|integer_exp\| positions to the left of the decimal point.

Time, Date, and Interval Functions

Function	Description
CURRENT_DATE( ) (ODBC 3.0)	Returns the current date.
CURRENT_TIME[( time-precision )] (ODBC 3.0)	Returns the current local time. The time-precision argument determines the seconds precision of the returned value
DAYNAME( date_exp ) (ODBC 2.0)	Returns a character string that contains the data source–specific name of the day (for example, Sunday through Saturday or Sun. through Sat. for a data source that uses English, or Sonntag through Samstag for a data source that uses German) for the day part of date_exp.
DAYOFMONTH( date_exp ) (ODBC 1.0)	Returns the day of the month based on the month field in date_exp as an integer value in the range of 1–31.
DAYOFWEEK( date_exp ) (ODBC 1.0)	Returns the day of the week based on the week field in date_exp as an integer value in the range of 1–7, where 1 represents Sunday.
HOUR( time_exp ) (ODBC 1.0)	Returns the hour based on the hour field in time_exp as an integer value in the range of 0–23.
MINUTE( time_exp ) (ODBC 1.0)	Returns the minute based on the minute field in time_exp as an integer value in the range of 0–59.
MONTHNAME( date_exp ) (ODBC 2.0)	Returns a character string that contains the data source–specific name of the month (for example, January through December or Jan. through Dec. for a data source that uses English, or Januar through Dezember for a data source that uses German) for the month part of date_exp.
QUARTER( date_exp ) (ODBC 1.0)	Returns the quarter in date_exp as an integer value in the range of 1–4, where 1 represents January 1 through March 31.
WEEK( date_exp ) (ODBC 1.0)	Returns the week of the year based on the week field in date_exp as an integer value in the range of 1–53.

Examples

A. Using an ODBC function in a stored procedure

The following example uses an ODBC function in a stored procedure:

CREATE PROCEDURE dbo.ODBCprocedure
    (
    @string_exp nvarchar(4000)
    )
AS
SELECT {fn OCTET_LENGTH( @string_exp )};

B. Using an ODBC Function in a user-defined function

The following example uses an ODBC function in a user-defined function:

CREATE FUNCTION dbo.ODBCudf
    (
    @string_exp nvarchar(4000)
    )
RETURNS int
AS
BEGIN
DECLARE @len int
SET @len = (SELECT {fn OCTET_LENGTH( @string_exp )})
RETURN(@len)
END ;

SELECT dbo.ODBCudf('Returns the length.');
--Returns 38

C. Using an ODBC functions in SELECT statements

The following SELECT statements use ODBC functions:

DECLARE @string_exp nvarchar(4000) = 'Returns the length.';
SELECT {fn BIT_LENGTH( @string_exp )};
-- Returns 304
SELECT {fn OCTET_LENGTH( @string_exp )};
-- Returns 38

SELECT {fn CONCAT( 'CONCAT ','returns a character string')};
-- Returns CONCAT returns a character string
SELECT {fn TRUNCATE( 100.123456, 4)};
-- Returns 100.123400
SELECT {fn CURRENT_DATE( )};
-- Returns 2007-04-20
SELECT {fn CURRENT_TIME(6)};
-- Returns 10:27:11.973000

DECLARE @date_exp nvarchar(30) = '2007-04-21 01:01:01.1234567';
SELECT {fn DAYNAME( @date_exp )};
-- Returns Saturday
SELECT {fn DAYOFMONTH( @date_exp )};
-- Returns 21
SELECT {fn DAYOFWEEK( @date_exp )};
-- Returns 7
SELECT {fn HOUR( @date_exp)};
-- Returns 1 
SELECT {fn MINUTE( @date_exp )};
-- Returns 1
SELECT {fn MONTHNAME( @date_exp )};
-- Returns April
SELECT {fn QUARTER( @date_exp )};
-- Returns 2
SELECT {fn WEEK( @date_exp )};
-- Returns 16

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